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Factor Binomials: -3x^2+7x

Kumon's Math Study Guide provides this question: Know how to "factor" Binomials: Problem: -3x^2 + 7x Answer: 0, 7/3 I thought the obvious answer is pulling out the x for the original binominal which would result in x (-3x+7) Although I haven't seen this before, I could take each of the factors and have them equal zero to come up with the answer. Am I missing something? Example: x = 0 and -3x + 7 = 0 Solve for x, x = 0 and x = 7/3

Question by bseibert    |  last reply


how to factor a 4 degree polynomial?

How would I solve an equation similar to this purely by using algebra, no graphing as I want exact answers. For those people that don't like helping people on homework, I have to say this. I have like 20 problems like this, and I just want to get down how to solve them.x3 -3x>x2 + 7btw the class is pre-calc

Topic by guyfrom7up    |  last reply


CFL power factor and how to correct? Answered

I have installed solar pv on my house and using a killawatt meter I have been checking the power factor and they are pretty bad .7.  Residential metering dont charge for power factor but when the solar pv is operating I believe the losses are coming from the pv power generated. Does anyone know of a CFL with a good power factor? I have heard that the power factor for the CFL's could be corrected with a .50 cent part. I believe that would be a capacitor but what size and how could you add it?   ?

Question by Riksmgb    |  last reply


What factors affect signal strength?

I made a signal boosting rig out of cardboard and aluminum for my router for my PS3 to access it ('cause I can't move the router in my current situation). So anyways it started out boosting a 17% average signal strength to a strong 50%. But now a couple of months later, it's maxing out at 23% and it's been happening for a couple of weeks now. Also, my ps3 absolutely refuses to work with anything below 25%. So what changed? I haven't moved the rig since I set it up and none of the furniture has moved either. The only factor I can think of is the changing of the seasons. Anything else that could of caused this?

Question by Ausm    |  last reply



What are the important factors to consider when I need to advertise using print stickers? Answered

What are the important factors to consider when I need to advertise using print stickers

Question by reezegardner    |  last reply


Capacitor quick question: (Dissipation factor vs ESR?)

I want a decent small capacitor that is suitable for "high power resonant circuits." On the osciloscope, the waveform looks like 2 well rounded humps, one that is skinny and tall and one shortly following that is shorter but longer, and this is periodic at 30KHz. UPDATE: looking at the waveform closer, it is clearly a damped ringing that is a bit trimmed. The screenshot is uploaded. The maximum measured slew rate was about 25.5MV/S, (which is 25.5V/uS, right?) for a "perfect" 1uF capacitor, that is a peak current of 25.5A! I am unsure of the RMS current due to the non-sinusoidal nature of this waveform. But it must be pretty high as well, explaining why my 3, 1cm diameter 3cm long 0.47uF MMC film capacitors get pretty warm.   . Why do some film capacitor datasheets only give dissipation factor ratings at a few test frequencies (like 10KHz and 100KHz) and others give ESR ratings as well? . Based on what I googled, I figured out dissipation factor is the ratio of ESR to the capacitive reactance. And since the frequency and capacitance is given it is not hard to calculate the ESR. So then why is this not conveniently already listed on the datasheet? Is it because the dissipation factor is what is directly measured? (like the total measured impedance of the capacitor at a certain test frequency)

Question by -max-    |  last reply


Extremely small arduino using dip16 form factor?

I am looking for a extremely small arduino board close to this one that I have.-> www.anatools.com/anarduino-kit/ I want a smaller form factor and I dont need need the serial headers, or even the extended sides as I can solder strait to the headers. I tried making my own board using eagle, and diptrace but I am running into alot of issues making it so compact. I was wondering if anyone has already made a board and have to eagle files, or know of any eagle files that I can have so I can etch my own board. Any help would be great! Thanks!

Question by newrev426    |  last reply


Where to find a small form factor 12v Battery?

I am looking to build an LED light that can be powered directly by a 12v source or use an internal battery. I expect that the fixture form factor will be about 4" in length by 2" to 2.5" in width and no more than 3/4" in depth. Internally, it needs to fit two LED units (each draws 0.1-0.2amps and only one would be on at a time) that are 1"x1"x5/8" each, the inside component of a single pole double throw waterproof switch and the remaining space for batteries. I would like to fit the maximum amount of available capacity as possible in as small a space as possible. I am looking for battery suggestions - small form factor, 12v, preferably available via a regular source (i.e. don't have to be special ordered from China), low self-discharge rate, ability to withstand temperature extremes (specifically 120F-140F degree heat). I'll consider wiring up batteries in parallel and serial to get the charge depth and the proper voltage. Any thoughts? I looked at A23 12v batteries and 2CR-1/3N 6v batteries (wire in serial) but I'd like to find something with more available capacity. Also, I'd prefer a non-toxic battery, but will consider lithium, and the ability to be recharged would be a big bonus. I'm guessing there's nothing out there that would give me enough life to be happy, but I thought I'd ask. Thanks!

Question by kcls    |  last reply


how do i factor the polynomial x^4-2x^2 1-a^2 by grouping?

How do i factor the polynomial x^4-2x^2 1-a^2 by grouping?

Question by amythibodeaux1    |  last reply


I want to make a power factor meter using arduino which can also show Real,Apparent and reactive power.

I want to make a power factor meter using arduino which can also show Real,Apparent and reactive power.

Topic by KaroonjharN  


Hard drive price confusion

Looking to create a small form factor PC to fit on the back of a monitor and while searching for a hard drive on Newegg noticed that the lowest price 2.5" internal desktop hard drive was $120 and not even 150GB ( http://tiny.cc/01012 ) while a 2.5" USB powered portable hard drive that is 1TB is $90 ( http://tiny.cc/01024 ), these numbers just are not adding up, couldn't I just disassemble the portable hard drive. Not sure if I am missing something important, Help is greatly appreciated!

Question by Algag    |  last reply


What are some of the factors to take care of while designing an EMI/RFI shielded Enclosure?

Are there any constraints on material used and wall thickness?

Question by vinod nicholas    |  last reply


What about sidewalk planting,should symmetry play a factor?

I am planning to plant beside my sidewalk,one side is sun,the other part shade,how to choose the correct edging plants,and what about symmetry?

Question by cathycarr    |  last reply




what makes collector current to be beeta(current amplification factor) times base current?

What makes collector current to be beeta(current amplification factor) times base current? Is it because of shape of the transistor or doping? or Why it is acting as constant current source? or Why the collector current is independent on collector resistor and Vcc(voltage across collector and emitter)?

Question by deepakmurali    |  last reply


How Would i go about making a hanglider if cost wasnt a factor??

I want to build a legit hanglider not one of those really sketchy home made ones i realize this is horribly dangerous but its something i have to do.

Question by TheKingsDuggie    |  last reply


What happened to Helene RubInstein ? Answered

Helena Rubinstein: cosmetics, face care, sun care, makeup. Well Max Factor..... ;)

Question by iceng    |  last reply


looking at earthbag with soil/clay fill , what area is considered cold? ?

What is the R factor of an earth bag wall

Question by mike poind    |  last reply


12v car heaters

12v 120w car heater should draw 10amp per hr and 50amp in 5 hrs , is this correct or is there other factors effects this guesstimate?

Question by celalboz    |  last reply


Does anybody know a good substitute for asbestos?

I need something that won't burst into flames, but I also don't want lung cancer. Any ideas? Availability is a big factor here.

Topic by carbon    |  last reply


I couldn't resist posting this, what do you think about this description?

Description: High quality, high effective and high stability. Display the error code by the result of TQST, then you could soon determine the error in error code table. Monitoring whether the card itself is fault or not permanently. And it will also inform users with the codes when there is something wrong with the cards itself so that avoid misleading users because of the fault of card itself. CPU did not work leading to inability of traditional diagnostic card, the diagnostic card can help you find the reason the traditional diagnostic card doesn't work, you can continue to test the motherboard with traditional diagnostic card after troubleshooting. The diagnostic card do not need new version information of BIOS, meaning of codes is clear, accurate and complete. It can monitor characteristics of post code of BIOS the whole process and reduce the misleading to users caused by traditional diagnostic cards. Completely break the limitations of function of traditional diagnostic cards, not only the standard interface of PCD, but also innovate various auxiliary security parts of improving the accuracy and reliability. Stability test card can tell you whether your computer is stable or not, no matter your computer works stable or unstable. And it also can help find the factors, not matter are invariable factors or variable factor as occasional and invisible potential factors.  

Question by Vyger    |  last reply


12vdc to 5vdc

Can anyone help me, I need a way to convert 12vdc from a vehicle battery to 5vdc for an application that I am working on. I need to do this in a way that it will not fail quickly, and also on the smallest form factor that I can.

Topic by janders223    |  last reply


I made chile with a habanero pepper; it is inedible. Anything I could add to the chile to reduce the heat factor?

I would hate to throw 3 lbs of ground sirloin away..any ideas what would cool the chili off?

Question    |  last reply


how effective is this airflow design? Answered

I am working on a very small build pc, and i was thinking that the best way to reduce overall height would be to design a cover piece that directs the airflow from the intake fanover the CPU and northbridge heatsinks and out the back of the unit via an exhaust fan. this method was chosen because the fan cannot be on top of the cpu heatsink because the unit would be too bulky if it was. I have attached a crude image of the planned cover and the layout of the board's heatsinks, and i would like to know if this is a effective method for cooling, in such a small form factor. if it isn't, what is?

Question by zack247    |  last reply


How Do Contests Work?

How does the member voting influence the contests? I thought that i was the driving factor, but after reading the rules I can't tell if it is even taken into account because of the way the judging is described.

Topic by longp2000    |  last reply


chemicals that expand when mixed

Can you guys give me a list of some chemicals that expand when mixed? the reaction's can't be combustion reactions though. that's the only limiting factor.

Topic by mexx.admin    |  last reply


my brother is building a recumbent motorcycle (feet first) can anyone recomment a good tech manual for this?

He is a low tech sort of guy so hard copy manual is best, but not essential. oh time is a factor as his birthday approacheth!

Question by maninamousesuit    |  last reply


What is the cheapest way to make plasma? Answered

I want to be able to shoot plasma out of a coilgun, but I want to know the cheapest way to generate it and other factors involved in doing this ( I.E. would it melt my gun and how to prevent this.). Any relevant information is welcomed.  

Question by StartedBullet    |  last reply


What's Wrong With My Code or My Sensors?

Hey gotta question! So I made an i'ble on how to make your own mini temperature sensor, and it worked great for a while, but after time, the temperature settings started getting more off and off. So what's wrong? I have the right conversion factors! If you go look at the Lm35's data sheet, I have all the conversion factors to convert the analog out from the LM35 to a degrees. Every time I use the LM35 with my arduino, it seems to work OK at first, the slowly slip and get worse. Now on the LM35's data sheet there are 2 schematics for wiring the sensor, should I use the schematic with the resistor for more accurate readings? Thanks!

Topic by HavocRC    |  last reply


I need a small FM radio tuner that can be set up for presets?

I need a small form factor FM frequency radio with tuner that can be set up for presets and to a plug in power supply To be used on a exercise machine. It also needs a headphone jack.

Question by fiteqprpr  


pricing model for 3D printed artifacts

What would be the factors affecting the pricing of 3D printed artifacts obviously - material used, time taken to print, any post processing steps should be considered. Any other things pop in to your mind. Please let me know.

Topic by 3dgeek    |  last reply


how do dust affect my performance in my computer?

How can i explain this factors which affect my computer! 1.Excessive temperature 2.Human being 3.Power outrage 4.Corrosion 5.Viruses 6.noise 7.Dust building up

Question    |  last reply


how to build a mesh dish for 5.8ghz amateur television transmissions. It needs to fold up for transport? Answered

I want to be able to construct two dish for 5.8ghz use. I want to be able to perhaps back pack the gear to a mountain top so weight is a factor cheers Colin VK2JCC Sydney Australia

Question by colincolin30    |  last reply


How does an inductor cause current to lag voltage in the case of an alternating current, and why is this bad? Answered

Basically, can someone help me with this: http://www.alpharubicon.com/altenergy/understandingAC.htm ? What are the EXACT physics behind it?

Question by Xellers    |  last reply


Looking for Info On These CNC Motors For Replacement

I purchased a surplus 2-axis CNC machine with built by Yamaha. I hoped to rebuild it into a new machine for myself, but it ended up requiring 200 volts AC for the controller and motors, which I don't have access to. I sold off the controller already. I don't know too much about professional CNC macahines, hoping someone has some input. I am hoping to replace the motors with ones in the same form-factor that run on DC or 120v AC(if such thing exists), preferably stepper type. I do not know what form-factor/package/mounting style to look for, or even if any are available with the power requirements I want.  Motors are the same for both axis and are part#: TS2620N664E122, attached are some pictures. Thanks,

Topic by ChromationSystems    |  last reply


What's the opposite of a header called?

What's the opposite of a header called (in electronics)? Like if I was searching mouser, what would I call it? A header receptacle? I dunno Basically I want a 2x3 socket thingamadousy for programming AVRs. In my ned project space is a factor and I need the 2x3 instead of 2x5

Topic by guyfrom7up    |  last reply


Ears Popping While Running?

Whenever I run a 5k, I'm finding that my ears start to pop part way through. It makes everything louder, including my breathing, and is extremely distracting. One website mentioned dehydration as a factor, another said something about blood pressure...does anyone know about it? Thanks!

Topic by Weissensteinburg    |  last reply


"Best" 3D Printer on the market today

Many of the 3D Printer reviews are a more than a year old that I have found. So the question is what is the "best" 3D printer and/or Printer Kit for someone who wants to start 3D printing. Cost is an obvious factor, but quality to finished product and simplicity for a beginner are also important. 

Topic by cadams15    |  last reply


Redneck Rollercoaster

This is called the Redneck Rollercoaster, but that's not quite the truth. This is an insane car mod that looks fun as hell and has the danger factor to bump it up to make it extra stupid. So who doesn't love some stupidly dangerous fun? Weirdos. Who loves it? Canadians.FYI, the guy on the left on the sofa is the driver. And how it works...

Topic by fungus amungus    |  last reply


capacitor resistance

Why is it that as super capacitors capacitance goes up the internal resistance goes down? I'm looking for a tiny capacitor that can supply 0.3 volts20mA (I'm going to be powering flexinol, not an LED) for 1 second. I don't want the capacitor to be huge because I'm making a beam bot where size is a factor for charging time and because of it's physical size.

Topic by guyfrom7up    |  last reply


Can anyone recommend a project for me to do in the summer holidays?

It needs to be reasonably cheap (sub £150) but there isn't really a time constraint, as I have about 8 weeks with nothing to do. I will try almost anything but if it involved welding that would have to be factored into the cost and time as I neither know how nor have the equipment.

Question by frazzlemydrive    |  last reply


How can I make a biodegradable adhesive in a paintball-like form-factor that's durable but would break if thrown.

Scenario: you're riding your bike. A car cuts you off. You have a little hopper full of these balls and have the presence of mind to get one out and throw it at the car. It sticks to the car. When the driver gets home, he sees it. Inside of the clear adhesive is a laminated piece of paper or something durable with a link written on it. The driver goes to the website and reads instructions about how to be a better bike-friendly driver. They wash the adhesive off with no damage done to the car. They become more conscientious drivers.

Question by pyaranderson    |  last reply


video over xbee

HELP I am constructing a airplane drone with rc capibilitys. I am wondering if there is a way to send video long range with high power xbees. if possible could someone post an instructable on it? Im shure it would help many people. also cost is a factor over the price of the xbees there shouldent be much more cost.

Topic by mrmarshall1    |  last reply


Why the parsimonious ratings?

Since the staff changed the ratings paradigm, I've seen only one instructable with a rating of 4 or above. And I've personally rated a few with 4.5.... Why are we suddenly so stingy with our ratings? (Is it like the "negative rating" days? down-rating because we can?) Or is the new system weighted, also? (with views, etc., factored, too?)

Topic by gmoon    |  last reply


Best price for PCB? Answered

Hi,   I am looking to make one PCB with dimensions 7"x7". I know that this is rather large, but was wondering if anyone knew the cheapest place to have this made as long it is decent quality? Time is not an important factor. It will probably be 2 layers, 4 at most. I know about Sparkfun's BatchPCB service. Thanks for your help.

Question by Hammock Boy    |  last reply


How to take a PC DVD Drive and make it a stand alone DVD player?

Yes, I know I can use one of the many small form factor PC's out there...but what other ways can I use to achieve the goal of taking a pc based internal DVD Rom and getting it to work as a standalone dvd player.....

Question by IdeaVault    |  last reply


Stepper Motor Library

Hi! Sorry, I was unable to put library below. So simple and yet so not so simple. How do I get the library in the folder so the program compiles/? Thanks 56Frank library for 28BYJ48 Stepper motor and ULN2003 driver. Here is the source code for our 28BYJ48 stepper motor, ULN2003 driver library, as well as an implementation. Check out the diagram for the wiring. The header file: __________________________________________________________________ #ifndef Stepper_h #define Stepper_h class StepperMotor { public:     StepperMotor(int In1, int In2, int In3, int In4);    // Constructor that will set the inputs     void setStepDuration(int duration);    // Function used to set the step duration in ms     void step(int noOfSteps);    //    for(int sequenceNum = 0;  sequenceNum <= noOfSteps/8; sequenceNum++){         for(int position = 0; ( position < 8 ) && ( position < ( noOfSteps - sequenceNum*8 )); position++){             delay(duration);             for(int inputCount = 0; inputCount < 4; inputCount++){                 digitalWrite(this->inputPins[inputCount], sequence[(int)(3.5 - (3.5*factor) + (factor*position))][inputCount]);             } Arduino         }     } } _______________________________________________________________________ An implementation: _______________________________________________________________________ #include StepperMotor motor(8,9,10,11); void setup(){   Serial.begin(9600);   motor.setStepDuration(1); } void loop(){   motor.step(1000);   delay(2000);   motor.step(-1000);   delay(2000); } Step a certain number of steps. + for one way and - for the other     int duration;    // Step duration in ms     int inputPins[4];    // The input pin numbers }; #endif ___________________________________________________________________ The cpp file: ___________________________________________________________________ #include #include StepperMotor::StepperMotor(int In1, int In2, int In3, int In4){     // Record pin numbers in the inputPins array     this->inputPins[0] = In1;     this->inputPins[1] = In2;     this->inputPins[2] = In3;     this->inputPins[3] = In4;     // Iterate through the inputPins array, setting each one to output mode     for(int inputCount = 0; inputCount < 4; inputCount++){         pinMode(this->inputPins[inputCount], OUTPUT);     }     duration = 50; } void StepperMotor::setStepDuration(int duration){     this->duration = duration; } void StepperMotor::step(int noOfSteps){     /*         The following 2D array represents the sequence that must be         used to acheive rotation. The rows correspond to each step, and         the columns correspond to each input. L     */     bool sequence[][4] = {{LOW, LOW, LOW, HIGH },                           {LOW, LOW, HIGH, HIGH},                           {LOW, LOW, HIGH, LOW },                           {LOW, HIGH, HIGH, LOW},                           {LOW, HIGH, LOW, LOW },                           {HIGH, HIGH, LOW, LOW},                           {HIGH, LOW, LOW, LOW },                           {HIGH, LOW, LOW, HIGH}};                           int factor = abs(noOfSteps) / noOfSteps;    // If noOfSteps is +, factor = 1. If noOfSteps is -, factor = -1     noOfSteps = abs(noOfSteps);    // If noOfSteps was in fact negative, make positive for future operations     /*         The following algorithm runs through the sequence the specified number         of times     */

Topic by 56Frank    |  last reply


View spikes on Instructables

Ok, so I was looking at my stat chart, viewing each Instructable individually, and I noticed something. On the day it is published, it gets a few views, and then the next day, there is a large spike and then it goes down again in the following days. How do you get your Instructable to have a more consistent view rate? Does it have to have a big "wow" factor? 

Topic by darman12    |  last reply